DERIVATIVES AND HEDGING ACTIVITY (UNITED DOMINION REALTY, L.P.) - Interest Rate Derivatives (Details) $ in Thousands	Dec. 31, 2019 USD ($) item instrument
Derivatives
Interest rate cash flow hedge gain (loss) to be reclassified during next 12 months, net	$ 1,700
United Dominion Realty L.P.
Derivatives
Interest rate cash flow hedge gain (loss) to be reclassified during next 12 months, net	$ 0
Interest rate swaps \| Designated as Hedging Instrument
Derivatives
Number instruments \| item	4
Notional	$ 315,000
Interest rate caps \| Not Designated as Hedging Instrument
Derivatives
Number instruments \| instrument	1
Notional	$ 19,880
Interest rate caps \| United Dominion Realty L.P. \| Not Designated as Hedging Instrument
Derivatives
Number instruments \| instrument	1
Notional	$ 19,880

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Nominal or face amount used to calculate payment on derivative.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5580258-113959

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
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-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5579245-113959

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The estimated net amount of unrealized gains or losses on interest rate cash flow hedges as of the balance sheet date expected to be reclassified to earnings within the next twelve months.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=112277219&loc=d3e80748-113994

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- Definition

Number of interest rate derivative instruments held by the entity at the reporting date.

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